1. Field of the Invention
This invention relates to a method and apparatus for reinforcing soil by improving the stiffness of soil.
In a further respect, the invention relates to a method and apparatus for constructing a structure at a selected building site.
In another respect, the invention relates to a method and apparatus for inexpensively improving the stiffness of soil supporting freeway embankments, water tanks, and other large loads which occupy large areas of ground, especially in situations where the soil supporting the large load is soft and is compressible by relatively light loads.
In still a further respect, the invention relates to a method and apparatus for supporting smaller structures, including buildings, storage silos, etc. which generate a smaller load on soil and occupy smaller areas of ground.
2. Description of the Related Art
My U.S. Pat. No. 5,249,892 describes aggregate piers which are constructed to improve the stiffness of soil. Each aggregate pier is constructed by forming a cavity in the ground and by then compacting layers of aggregate in the cavity to form a substantially stiff, dense aggregate pier. Each aggregate pier is typically ten to forty-five times stiffer than soil. The aggregate pier and soil surrounding the pier comprise a cell which has a composite stiffness about five to fifteen times greater than the stiffness of the soil without the pier. Although the aggregate pier is effective in increasing the stiffness of soil, the pier has disadvantages. In particular, it is not practical to install an aggregate pier which extends to great depths. If it is therefore desirable to improve the stiffness of soil at depths of greater than about twenty feet, an aggregate pier is not practical. In addition, in some cases it is not necessary to stiffen soil to the degree provided by an aggregate pier.
Accordingly, it would be highly desirable to provide an improved method and apparatus for increasing the stiffness of soil at depth of up to one hundred and fifty feet and at a cost which is significantly less than the cost of utilizing aggregate piers.
Therefore, it is a principal object of the invention to provide an improved method and apparatus for stiffening soil.
A further object of the instant invention is to provide an improved method and apparatus for stiffening soil at depths of up to one hundred and fifty feet.
Another object of the invention is to provide an improved method and apparatus which can be utilized to stiffen soil at a cost which is significantly less than that encountered in using aggregate piers or other soil reinforcing systems.
These and other further and more specific objects and advantages of the invention will be apparent to those skilled in the art from the following detailed description thereof, take in conjunction with the drawings, in which:
FIG. 1 is a side elevation view illustrating apparatus being installed in the ground at a building site to improve the stiffness of soil comprising the ground;
FIG. 2 is a side elevation view of the apparatus of FIG. 1 illustrating further steps taken to install the apparatus in the ground at a building site;
FIG. 3 is a side elevation view illustrating a structure constructed at a building site using apparatus of the type shown in FIGS. 1 and 2;
FIG. 4 is a cross-section view of a portion of the apparatus of FIG. 2 illustrating further construction details thereof;
FIG. 5 is a side elevation view illustrating one procedure for installing in the ground at a building site the apparatus illustrated in FIGS. 1 and 2;
FIG. 6 is an elevation view illustrating another procedure for installing in the ground at a building site apparatus constructed in accordance with the invention;
FIG. 7 is a perspective view illustrating a rectangular plate utilized in the procedure illustrated in FIG. 6;
FIG. 8 is a perspective view illustrating another plate which can be utilized in the procedure illustrated in FIG. 6; and,
FIG. 9 is a section view taken along section line 9xe2x80x949 and illustrating further construction details of the procedure of FIG. 6.